Microstructure and electrical properties of Pr6O11–Co3O4–MnCO3–Y2O3-doped ZnO varistors

The microstructure and electrical properties of the ZPCMY varistor ceramics composed of ZnO–Pr6O11–Co3O4–MnCO3–Y2O3 systems sintered at temperature of 1200–1300 °C were investigated. The addition of Y2O3 led to the decrease of the densification and the slight improvement of the electrical properties. The varistor voltage decreased over a wide range from 7100 to 2470 V/cm with the increase of sintering temperature. The ZPCMY-based varistor ceramics sintered at 1275 °C exhibited the best performance in terms of the densification and E–J characteristics. These varistors were characterized by 5.27 in bulk density, 55.3 in the nonlinear exponent and 1.53 μA in the leakage current.